Several attempts have been made to adopt modern plastic technology to the production of rigid enclosures for such segments as a living body, human or animal. The use of rigid body and body member casts are important to assist in the healing of tissues and in knitting of fractures of the bone.
Such methods have incorporated systems, which have been disadvantageous for one of many reasons. For example, one method is dependent upon a closed plastic bag which is wrapped around the member and a plastic foam is allowed to develope in the bag. This system of encasement is slow, difficult to apply and very hot and uncomfortable for the wearer. The system does not allow air to enter or leave the appliance.
The conventional plaster of Paris systems have many dissatisfactory properties. Particularly, the casts formed therewith are heavy, X-ray impervious, absorb excessive moisture which thereby destroys the mechanical property, soil rapidly, are difficult to clean, poor shock resistance, lack elasticity, slow to reach ultimate strength, poor abrasive resistance and receptive to bacterial and fungal growth.
It also has been proposed to soften sheets of plastic materials and apply them to the part of the body to be immobilized so as to set upon cooling to a desired position. Unfortunately, the temperature to which such thermoplastic materials must be raised to make them moldable is too high to be endured by a patient unless an insulating intermediate material is first applied.
Certain systems and methods of casting have been proposed which utilize polymerizing systems and polymerizing bandages. However, these systems employ large amounts of liquid volatile and non-volatile diluents to replace part of the monomer as liquid extenders or wetting material. The presence of such volatile liquids are unsatisfactory. The presence of non-volatile viscous diluents do not cause vapor cells and form weak casts due to inadequate wetting of the solid filter or inability to satisfactorily dissolve the polymer formed and the like. Various catalyzed and accelerated mixtures of monomeric solvents within the prior diluent systems attempt to overcome the disadvantages thereof by addition of non-polymerizable polyalcohol esters. The problem of noxious volatile fumes remains. This is highly undesirable when such a system is used in a confined area. Further, the method for body use requires the coating of the body member with petrolatum or other protectant, this prevents air from reaching the injured member.
The prior art, U.S. Pat. No. 3,089,486, discloses a methacrylate polymer impregnant which is imbued into a bandage. The bandage in this form can be stored, however, this requires constant monitoring to insure a usable material. Further, the system described therein requires applying a barrier to the body member prior to applying the monomer component. This presents the disadvantage of placing an air impervious barrier which allows moisture to collect under the barrier from body prespiration, thereby inducing skin irritation.
Means, in U.S. Pat. No. 2,576,027, describes impregnating a cloth such as surgical gauze or the like, with a chemical that acts as a catalyst with reference to a solution of a synthetic resin. The solution of synthetic resin is applied to the gauze to form a rigid solid. The catalyst and synthetic resin relates to a specific urea-formaldehyde system. The catalyst system described by Means is not effective in curing vinyl-type monomers and cannot be used with the instant invention.
The prior art, U.S. Pat. Nos. 3,421,501 and 3,613,675, describe bandages which contain an activated resin. The bandages are cured by exposure to ultraviolet light.